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Docs for snapshots as simple archives #86261
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[cols="^,^,^,^,^"] | ||
[cols="^,^,^,^,^,^"] | ||
|==== | ||
| 4+^h| Cluster version | ||
h| Index creation version | 6.8 | 7.0–7.1 | 7.2–{prev-major-last} | 8.0–{minor-version} | ||
| 5.0–5.6 | {yes-icon} | {no-icon} | {no-icon} | {no-icon} | ||
| 6.0–6.7 | {yes-icon} | {yes-icon} | {yes-icon} | {no-icon} | ||
| 6.8 | {yes-icon} | {no-icon} | {yes-icon} | {no-icon} | ||
| 7.0–7.1 | {no-icon} | {yes-icon} | {yes-icon} | {yes-icon} | ||
| 7.2–{prev-major-last} | {no-icon} | {no-icon} | {yes-icon} | {yes-icon} | ||
| 8.0–{minor-version} | {no-icon} | {no-icon} | {no-icon} | {yes-icon} | ||
| 5+^h| Cluster version | ||
h| Index creation version | 6.8 | 7.0–7.1 | 7.2–{prev-major-last} | 8.0–8.2 | 8.3-{minor-version} | ||
| 5.0–5.6 | {yes-icon} | {no-icon} | {no-icon} | {no-icon} | {yes-icon}footnote:archive[Using <<archive-indices,archive>> functionality] | ||
| 6.0–6.7 | {yes-icon} | {yes-icon} | {yes-icon} | {no-icon} | {yes-icon}footnote:archive[] | ||
| 6.8 | {yes-icon} | {no-icon} | {yes-icon} | {no-icon} | {yes-icon}footnote:archive[] | ||
| 7.0–7.1 | {no-icon} | {yes-icon} | {yes-icon} | {yes-icon} | {yes-icon} | ||
| 7.2–{prev-major-last} | {no-icon} | {no-icon} | {yes-icon} | {yes-icon} | {yes-icon} | ||
| 8.0–8.2 | {no-icon} | {no-icon} | {no-icon} | {yes-icon} | {yes-icon} | ||
| 8.3–{minor-version} | {no-icon} | {no-icon} | {no-icon} | {yes-icon} | {yes-icon} | ||
|==== |
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[[archive-indices]] | ||
== Reading indices from older {es} versions | ||
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{es} has full query and write support for indices created in the previous major | ||
version. If you have indices created in {es} versions 5 or 6, you can now use | ||
the archive functionality to import them into newer {es} versions as well. | ||
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The archive functionality provides slower read-only access to older {es} data, | ||
for compliance or regulatory reasons, the occasional lookback or investigation, | ||
or to rehydrate parts of it. Access to the data is expected to be infrequent, | ||
and can therefore happen with limited performance and query capabilities. | ||
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For this, {es} has the ability to access older snapshot repositories | ||
(going back to version 5). The legacy indices in the <<snapshot-restore,snapshot repository>> | ||
can either be <<restore-snapshot-api,restored>>, or can be directly accessed | ||
via <<searchable-snapshots,searchable snapshots>> so that the archived data | ||
won't even need to fully reside on local disks for access. | ||
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[discrete] | ||
[[archive-indices-supported-field-types]] | ||
=== Supported field types | ||
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Old mappings are imported as much "as-is" as possible into {es} 8, but only | ||
provide regular query capabilities on a select subset of fields: | ||
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- <<number,Numeric types>> | ||
- <<boolean,`boolean` type>> | ||
- <<ip,`ip` type>> | ||
- <<geo-point,`geo_point` type>> | ||
- <<date,`date` types>>: the date `format` setting on date fields is supported | ||
in so far as it behaves similarly across these versions. In case it is not, | ||
for example {ref-7x}/migrate-to-java-time.html[when using custom date formats], | ||
this field can be updated on legacy indices so that it can be changed by a | ||
user if need be. | ||
- <<keyword-field-type,`keyword` type>>: the `normalizer` setting on keyword | ||
fields is supported in so far as it behaves similarly across these versions. | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. here too "is supported as long as..." |
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In case it is not, this field can be updated on legacy indices if need be. | ||
- <<text-field-type,`text` type>>: scoring capabilities are limited, and all | ||
queries return constant scores that are equal to 1.0. The `analyzer` | ||
settings on text fields are supported in so far as they behave similarly | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. supported as long as ? |
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across these versions. In case they do not, they can be updated on legacy | ||
indices if need be. | ||
- <<multi-fields,Multi-fields>> | ||
- <<field-alias,Field aliases>> | ||
- <<object,`object`>> fields | ||
- some basic metadata fields, e.g. `_type` for querying {es} 5 indices | ||
- <<runtime-mapping-fields,runtime fields>> | ||
- <<mapping-source-field,`_source` field>> | ||
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{es} 5 indices with mappings that have {ref-7x}/removal-of-types.html[multiple mapping types] | ||
are collapsed together on a best-effort basis before they are imported. | ||
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In case the auto-import of mappings does not work, or the new {es} version | ||
can't make sense of the mapping, it falls back to importing the index without | ||
the mapping, but stores the original mapping in the <<mapping-meta-field,_meta>> | ||
section of the imported index. The legacy mapping can then be introspected | ||
using the <<indices-get-mapping,GET mapping>> API and an updated mapping can | ||
be manually put in place using the <<indices-put-mapping,update mapping>> API, | ||
copying and adapting relevant sections of the legacy mapping to work with the | ||
current {es} version. While auto-import is expected to work in most cases, | ||
failures of doing so should be raised with the Elastic team for future | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. link to open an issue? |
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improvements. | ||
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[discrete] | ||
=== Supported APIs | ||
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Archive indices are read-only, and provide data access via the | ||
<<search-search,search>> and <<search-field-caps,field capabilities>> APIs. | ||
They do not support the <<docs-get,Get API>> nor any write APIs. | ||
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Archive indices allow running queries as well as aggregations in so far as | ||
they are <<archive-indices-supported-field-types,supported by the given field type>>. | ||
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Due to `_source` access the data can also be <<docs-reindex,reindexed>> | ||
to a new index that has full compatibility with the current {es} version. | ||
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[discrete] | ||
=== How to upgrade older {es} 5 or 6 clusters? | ||
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Take a snapshot of the indices in the old cluster, delete indices that are not | ||
directly supported by ES 8 (i.e. indices older than 7.0), upgrade the cluster | ||
without the old indices, and then <<restore-snapshot-api,restore>> the legacy | ||
indices from the snapshot or <<searchable-snapshots-api-mount-snapshot,mount>> | ||
them via searchable snapshots. | ||
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In the future, we plan on streamlining the upgrade process going forward, | ||
making it easier to take legacy indices along when going to future major | ||
{es} versions. |
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what do you mean with "is supported in so far as it behaves similarly across these versions"?
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We have changed the meaning of various custom date formats / date literals across versions (e.g. year of era becomes week-based year), see https://www.elastic.co/guide/en/elasticsearch/reference/7.17/migrate-to-java-time.html#java-time-migration-incompatible-date-formats
Perhaps I could link to the above for additional context, as well as limit the scope of the problem to "custom date formats".
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sounds good to expand a bit, thanks.
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do you mean "is supported as long as it behaves similarly across versions"?